I am having problems understanding the concept of dynamic range, and more specific how the dynamic range of human hearing relates to the dynamic range as specified for audio equipment.

What I have read on the Net is that the dynamic range of human hearing is, on average, 135 dB (the pain limit / threshold?).

I also understand that the dynamic range of a CD (16 bit) is limited to 96 dB, and for HD (24 bit) recordings 144 dB. This dynamic range is calculated by the bit-depth.

For playback of music (I use 44.1/16 flac only) I use a E-MU 1820 that has a dynamic range of about 115 dB (or so). I am not sure what my amp can do...

However, when I play music I hardly pass 80 dB (or so) listening volume, so the 96 dB CD data (if the recording makes full use of the range that is) gets "compressed", while the relative dynamic range remains.

After the long intro my question in essence is:

Does the human hearing have a similar "resolution" that is comparable to the resolution defined by the bit-depth in (digital) audio? Or am I just comparing apples and pears?

I am ashamed to tell that, although the discussion has been very informative, I hve not been able to distill an answer for my question from it.

Sticking to CD specs, the 16-bit signed integers (-32768 to 32767; 65536) in my mind represent the steps to map the analogue waveform to. Since CD specs also state a 96.### dB dynamic range, it seems logical to me that the same 65536 steps also have a relation to the dB scale.

I am sure that, if we would map a waveform into 4 bits and played that waveform back at 96 dB, everybody would hear it as a rather coarse sound, and if we would lover the sound to 15 dB (theoretically, not taking into account background noise ) that same coarseness would be significantly lower. At some point however, if we increase the number of bits in which the waveform is coded in, the coarseness disappears, and the sound gets smooth enough.

There must be research done by Philips / Sony that would prove the 16 bits coding / mapping and the 96 dB were good enough for CD playback.

I am sure that, if we would map a waveform into 4 bits and played that waveform back at 96 dB, everybody would hear it as a rather coarse sound, and if we would lover the sound to 15 dB (theoretically, not taking into account background noise ) that same coarseness would be significantly lower.

You can give it a try yourself.

These are music excerpts reduced to an equivalent of 4 bits (or slightly more, IIRC).